Disposable diapers, as is well known, now find widespread use for infant care and have generally replaced the use of cloth diapers. The typical disposable diaper is a three-layer composite structure comprising a liquid permeable bodyside inner liner, a liquid impermeable outer cover and an absorbent batt sandwiched between the liner and the cover. Materials now in general use for the three principal elements of a disposable diaper include various types of nonwoven fabrics for the bodyside liner, a thin thermoplastic film for the outer cover and cellulosic fluff for the absorbent batt.
Disposable diapers of the type presently on the market are flat open-sided garments that are intended to be fit about an infant by a parent while the infant is lying down. The rear panel of the diaper is placed underneath the infant, and the front panel drawn between the infant's legs, after which the sides are overlapped and held together by pressure-sensitive adhesive tape. A diaper is meant for use when the child is young and dependent upon a parent for this essential purpose.
The popularity of disposable diapers has led to the belief that there is a demand for a disposable underpant, such as a disposable training pant, that can be used when a child grows out of a diaper. Diapers are typically used with infants up to about fifteen months old. When a child reaches an age in the range of about fifteen to thirty months, however, a parent generally desires to start toilet training so that the child can become independent of a parent. The training pant is intended for use when the child has reached an age at which he or she is ready to graduate to an underpant type of garment as a replacement for disposable diapers previously used. Thus, a suitable training pant must be a garment having closed sides so that a child can raise and lower it as necessary without requiring the aid of a parent. At the same time, a training pant must provide features of liquid and solid absorbency and prevent leakage of the waste fluids.
Cloth training pants, although widely-used, have disadvantages. Current cloth training pants have very little absorbency and often must be used with exterior rubber or plastic pants. When a child wets a cloth training pant, most often all of the child's clothes must be changed. Further, if a child has a bowel movement, it is difficult to remove a cloth pant without making a mess, and the pant must be soaked and bleached. All of these factors can make the toilet training process frustrating for both child and parent.
In addition, it is believed that the psychology of the toilet training stage is such that the child should perceive he or she is graduating to a garment that is different than a disposable diaper. The requirements for a disposable underpant such as a training pant are not satisfactorily met by the constructions of disposable diapers as currently known in the art. In this connection, for example, the typical disposable diaper, as stated previously, has an outer layer comprising a liquid-impermeable sheet of plastic film. Various techniques have been used to give the plastic sheet the feel and appearance of texture, but the exterior of the garment has a plastic feel or appearance which is closely associated with the concept of a diaper but would be inappropriate for a disposable training pant. Since the purpose of a training pant is to encourage the child to make the transition from diapers to washable or reusable cloth underpants, it is important that a disposable training pant simulate a cloth underpant as much as possible.
There has been proposed a particular desirable disposable underpant in U.S. Ser. No. 690,351, filed Jan. 10, 1985, with Inventors Heran et al. This disposable underpant while particularly desirable has a complication in its formation as the side seals are on the interior of the garment. The formation process involves the necessity of formation of the garment with the interior facing outward for side sealing after which the garment is reversed prior to packaging for sale. Reversing of the completed elasticized garment is an extra mechanical handling step that it would be desirable to eliminate as it is complicated and expensive. However, generally undergarments have been formed with inner side seams seals as the looks is improved by not having flaps on the outer surface. Further, the turning of the flaps to the inside of the garment has created additional difficulties in that the inside seals can be a source of skin irritation unless they are carefully formed. On the other hand, if exterior conventional seals are formed, they create flaps that have an undesirable appearance as it is intended that the garments resemble cloth underpants which do not have exterior seams. Therefore, there is a need for an exterior seal on a disposable garment that is discrete, strong, and easy to form.